A number of patents disclose certain N-aryl-N(1-substituted-4-piperidinyl) amides having analgesic activity. For example, U.S. Pat. Nos. 3,998,834, 3,164,600, and 4,167,574, issued to Janssen et al. and assigned to Janssen Pharmaceuticals N.V., disclose certain N-phenyl-N-[1-(aryl-substituted)-4piperidinyl]amide compounds, N-aryl-N-[1-(arylalkyl)-4-piperidinyl] amides and N-aryl-N-[1-(tetrazolyl-substituted)-4-piperidinyl]amides useful as analgesics. U.S. Pat. No. 4,584,303, issued to Huang et al. and assigned to The BOC Group, Inc., discloses certain J-phenyl-N-[1-(heterocyclic)-4-piperidinyl]amide compounds useful as analgesics.
U.S. Patent No. 4,138,492, issued to Noverola et al. and assigned to Anphar, S.A., discloses certain N-[4'(1'-arylalkyl)piperidinyl]-4-amino-5-halo-2alkoxy benzamide compounds. Van Daele et al., Drug Develooment Research, 225-232 (1986), discloses the preparation of certain 3-hydroxy-4,4-dimethoxy-1phenylmethyl piperidine derivatives.